Patent Literature 1 discloses a magnetic sensor device that includes: a conveyance path for conveying a to-be-detected object; a magnet having a magnetic pole arranged on one side of the to-be-detected object and generating a cross magnetic field crossing the to-be-detected object; a magnetoresistive effect element that is arranged between the magnet and the to-be-detected object, has an output terminal, and outputs a change in a component in the conveying direction in the cross magnetic field as a change in a resistance value, the change being caused by the magnetic component of the to-be-detected object conveyed in the cross magnetic field. Patent Literature 1 discloses, as a configuration of a magnetic circuit for generating a cross magnetic field, a configuration in which magnets are arranged to face each other across the to-be-detected object, and a configuration in which a magnet is arranged on one side of the to-be-detected object, and a magnetic body is arranged on the another surface thereof facing the magnet.
Patent Literature 2 discloses a magnetic sensor that includes: a board, a magnetoresistive effect element that has a pair of magnetosensitive portions arranged parallel to each other with a constant distance apart from each other on the board; a conductor layer arranged at a position from which each of the pair of magnetosensitive portions are at an equal distance; and a resistance electrically connected in series with the conductor layer.
Patent Literature 3 discloses a configuration to obtain a long magnetic circuit that uses a plurality of short magnets that are arranged in an array, and that has a uniform magnetic flux density distribution in the array direction.